On October 29, 2012, Oyster Creek declared a Notice of Unusual Event followed by an Alert due to high water levels in the intake structure. Elevated intake structure water levels are of concern as excessive levels can flood certain plant components and render normal cooling systems inoperable. No safety systems were adversely affected by the high intake level. The site also experienced a loss of offsite power. Both emergency diesel generators started as designed and supplied power to the emergency electrical busses. Shutdown cooling and spent fuel pool cooling were temporarily lost but subsequently restored, after the busses were reenergized. At 9:59 a.m. EDT on October 30, the licensee restored one line of off-site power via a start-up transformer. Oyster Creek terminated the Alert at 3:52 a.m. EDT on October 31 when water level dropped below 4.5 ft and off-site power was fully restored.